The effect of vaccinating turbot broodstocks on the maternal immunity transfer to offspring immunity

• The maternal transfer of immune genes and proteins both exists in turbot.
• Vaccinating brood stocks before spawning seasons could enhance the maternal transfer effect.
• The enhancing effect of vaccinating focused on the hatching process.
• Different kinds of immune factors have different variations during the experiment.

The study was designed to explore the effect of vaccinating turbot broodstocks on the immunity of offsprings. The expression of IgM, C3, TGF-β1, IL-1β, transferrin, lysozyme and their concentrations were detected respectively with quantitative real-time PCR and Elisa kits in offsprings at different stages from both naive and vaccinated brood stocks. The survival rate of offsprings in pathogen challenge experiment and their pathogen inhibition rate were also detected. The results shown that the maternal transfer of genes and proteins both existed in turbot. In the expression level, from eggs to 5 dpf (days past fertilization), the immune related genes expressed far more in vaccinated broodstocks offsprings, after hatching, the phenomenon disappeared. In protein level, transferrrin, C3 and IL-1β kept a stable level in concentration from eggs to 25 dph (days past hatching), and increased sharply at 45 and 55 dph. While, IgM and lyzozyme had a much higher concentration at 5 dpf in the embryos from vaccinated broodstocks, and we concluded that vaccinating broodstocks enhanced the production or maternal transfer of IgM and lyzozyme. Vibrio anguillarum challenge experiment showed that the vaccinated offsprings of 4 dpf and 14 dph had a better anti-pathogen ability than the ones from naive brood stocks. Throughout the study, it was concluded that vaccinating broodstocks could strength the maternal transfer of immune factors in gene and protein level, and the gene expression level during hatching was also enhanced at the early stage of development.